Integrally Bladed Rotors (IBR's), also commonly known as “bladed discs” are important parts of gas turbine engines. Manufacturing IBR's is a challenging task due to the complex geometry of airfoil surfaces. Existing methods of manufacturing IBR airfoils include flank milling, point milling, etc. In a flank milling process, the periphery of an end mill, typically a tapered ball end mill, generates the desired airfoil surface geometry through one or more passes of the cutter. The tool used in a point milling process is usually a tapered end style milling cutter, small enough such that the entire diameter of the tool can fit between the airfoils of the IBR. These milling cutters have cutting blades and flutes which either extend straight down the cutter, or can extend around the cutter in a helical direction. The helical blade arrangement is often preferred because when using that type of cutter, a portion of the blade is always in contact with the work piece and the blades tend to slice off cuttings rather than chip them away. The helix angle of such blades is conventionally about 10 to 40 degrees as measured from a line parallel to the rotational axis of the cutter. However, cutting tool geometry is very important to the process stability, repeatability, surface finishing and tool durability under certain cutting conditions on IBR's.
Accordingly, there is a need for optimization of milling cutters for machining IBR airfoils.